This invention relates to surgical instruments, and more particularly to protection of delicate instrument parts or the sharp points or blades located at a distal end of such surgical instruments, wherein the protection system prevents injury to a person or damage to the instrument.
Surgical instruments may include a sharp point or cutting blade. Others are extremely delicate. Examples of such instruments include hooks (such as Sinskey hooks, Bonn hooks, insertion hooks, twist hooks and the like), scissors (such as retinal scissors and the like), picks (such as retinal picks and the like), forceps, probes, lens manipulators, markers, collar buttons, choppers, cystotomes irrigation needles and cannulas, spatulas (such as Castroviejo spatulas and the like), and dilators. Most often, these instruments include at least one generally cylindrical handle with a distal end that houses a delicate member, sharp point, or cutting blade. Surgical knives that include a cutting blade at a distal end of the handle are typical of such instruments, and much of the prior art pertaining to protection for such instruments is directed at protection for surgical knives. However, the instant invention applies equally to the protection of non-sharp instruments.
Surgical instruments typically have a body with a cutting blade or other operable instrument at one end of the body. The end of the body with the instrument sometimes has a portion that tapers down towards the instrument to provide good visibility of the instrument tip. The instruments can be extremely sharp, and the extreme sharpness may render them hazardous when passed back and forth during use in surgical operations. If the instrument has already been used on the patient, then there is a potential danger of infection since any sharp or tapered instrument can very easily cut or rip through a surgical glove and the skin beneath the glove.
In general, prior art systems for protection of surgical knives include some form of mechanically operable shield that covers the cutting blade when not in use, and that may be moved or removed in order to expose the cutting blade during use. A discussion of the prior art  pertaining to protection for surgical knives is generally applicable to the different types of surgical instruments mentioned above.
U.S. Pat. No. 4,576,164 to Richeson discloses a disposable micro-surgical knife having a shroud that can be locked into a position protecting the blade. The shroud is in the form of a cylindrical sheath that moves axially along and around the knife body. In addition, the shroud has a plurality of projections which mate with a series of longitudinal and circumferential grooves formed in the exterior of the knife body. This arrangement of grooves on the knife body and projections on the shroud allow the shroud to be locked in two or three different axial positions on the knife body. In one position the shroud acts as an enlarged handle, and in a different position the shroud acts as a protective device for the blade and blade edges. However, if the shroud is damaged or slips off and is lost, then the knife body has undesirable grooves on its outer surface that may be uncomfortable to a surgeon using the knife.
U.S. Pat. No. 4,414,974 to Dodson, et al. discloses a surgical knife with a shroud similar to the one disclosed by Richeson. However, the surgical knife of Dodson et al. does not have a shroud with projections, and it does not have longitudinal or circumferential grooves on the exterior surface of the knife body. Instead, the surgical knife of Dodson et al. relies upon friction between oversized portions of the body and the opening in the shroud for a friction fit. In one axial position the shroud is retracted for use and in another axial position the shroud is in a blade protective position. However, if the friction fit is inadequate, the shroud may slip from its desired position thereby resulting in safety hazards and potential damage to the knife blade.
U.S. Pat. No. 4,735,202 to Williams discloses a disposable micro-surgical knife having a blade guard. The blade guard is basically a cylindrical sleeve that has a longitudinal slot that extends to one end of the sleeve. The knife body has a small locking tab adjacent the forward tapered portion of the knife. The blade guard slides onto the knife body from the rear until the locking tab enters the longitudinal slot and the guard is rotated to be locked into place. Thus, the blade guard can be locked into a blade covering position and then  totally removed from the knife body for use of the knife. However, this blade guard may be easily damaged or lost after removal, thereby defeating its purpose.
Similarly, U.S. Pat. No. 4,768,509 to Grosvenor et al. discloses a removable external blade guard. U.S. Pat. Nos. 3,706,106; 3,905,101; and 3,945,117 disclose other types of surgical knives having movable or removable blade protective structures. These knives suffer from the same or similar limitations as described above.
U.S. Pat. No. 5,254,128 to Mesa (incorporated herein by reference) discloses a surgical knife with a blade protector axially moveable between two positions, namely, opened for normal use and closed for storage or safe handling. The blade protector may be fixed in either position by two sets of threads, one set on the knife handle and another matching set at both ends of the blade protector. While this arrangement solves some of the limitations of the prior art described above, other common limitations still exist. For example, with the surgical knife of Mesa, debris is often trapped under the blade protector and between the opposing sets of male and female threads, thereby preventing or inhibiting thorough cleaning or sterilizing. In addition, safety concerns may arise due to the nearly uniform appearance of both ends of the surgical instrument body, thereby making it difficult to see which end of the body houses the instrument and what particular type of instrument is attached to the body, especially with small instruments which may be less than 3 millimeters in diameter. Moreover, the smooth outer surface of the blade protector makes it difficult to open or close the blade protector with one hand (as the factor considered by OSHA regulations pertaining to medical “sharps”), and often causes the surgical instrument to roll off the sterile field and potentially damage the instrument.
These and other limitations and disadvantages of the prior art are overcome by the present invention, which provides an improved protection system for surgical instruments, wherein the instrument is provided with a movable protector for preventing injury to handlers and damage to the instrument when not in use. 